The present invention relates to actuation of a flap on a wing or airfoil.
Flaps on aircraft wings serve a variety of purposes including, for example, a lift assist. These latter types of flaps are usually designed so that the flaps themselves as well as any actuating mechanism offers little drag resistance, particularly during cruising. This condition is particularly important for so-called supercritical wings being designed for low drag because the flap-guiding structure may, in effect, tend to increase that drag.
Flap actuations are, for example, of a rail construction; or newer and less expensive ones are designed as parallelograms for extending the flaps by means of hinge structures having horizontal axes. These structures require extensive covering for avoiding undue drag.
U.S. Pat. No. 2,973,925 describes a leading edge slat which is to be extended into a position in front of and below the airfoil by means of aerodynamic forces. When retracted, the slat actuation is covered by the slat. The movement of the slat is carried on a cylindrical or conical surface.